<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        *{
            margin: 0px;
            padding: 0px;
        }
        div{
            width:300px;
            height:300px;
            background-color: #ccc;
            margin:50px;
            display:flex;
            flex-direction: row;
            flex-wrap: wrap;
            align-items: center;
            justify-content: space-between;
        }
        div p{
            width:88px;
            height: 80px;
            /* flex:1; */
            border:1px solid red;
            /* margin-right:10px; */
            /* float:left; */
        }
        div p:nth-child(2){
            /* flex:2; */
            flex:initial;
            /* width:150px; */
            background-color: cadetblue;
        }
        /*
        div:300px-->300*50%=150px
        p:88+2+10-->88*50%+2+10=56px
        */
    </style>
</head>
<body>
    <div>
        <p>p1</p>
        <p>p2</p>
        <p>p3</p>
    </div>
</body>
</html>